# How to get all Green lights? **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [December 16, 2004, 9:25pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211 "2004-12-16T21:25:22Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![JustWrightin](https://avatars.discourse-cdn.com/v4/letter/j/a87d85/32.png) [@JustWrightin](https://boards.straightdope.com/u/JustWrightin)\ **Post date:** [December 16, 2004, 9:25pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/1 "2004-12-16T21:25:22Z")
Suppose if you are driving and the first light you encounter is green does that mean if you go the speed limit of what the signs tell you , you will keep going on greens and never have to stop on red? ((This is really depending on people driving decently and staying at the speed limit the whole time)) ---
**Author:** ![klintypooh](https://avatars.discourse-cdn.com/v4/letter/k/3da27b/32.png) [@klintypooh](https://boards.straightdope.com/u/klintypooh)\ **Post date:** [December 16, 2004, 9:28pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/2 "2004-12-16T21:28:50Z")
The woman from Bewitched used to wiggle her nose to do it, you could try that. 🙂 ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [December 16, 2004, 9:29pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/3 "2004-12-16T21:29:56Z")
Traffic light timers are sometimes be set up to be synchronous with average driving speed, sometimes as the result of complex traffic pattern predictions, and sometimes completely nonsensically. Further, some timers change their schedules during different parts of the day to accomidate unidirectional rush-hour traffic. So there is no one answer to this question. ---
**Author:** ![Severian](https://avatars.discourse-cdn.com/v4/letter/s/49beb7/32.png) [@Severian](https://boards.straightdope.com/u/Severian)\ **Post date:** [December 16, 2004, 9:32pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/4 "2004-12-16T21:32:05Z")
> [@friedo](#): > > Traffic light timers are sometimes be set up to be synchronous with average driving speed, sometimes as the result of complex traffic pattern predictions, and sometimes completely nonsensically. Further, some timers change their schedules during different parts of the day to accomidate unidirectional rush-hour traffic. So there is no one answer to this question. Not to mention those that change based on the presence of a vehicle waiting at a red. ---
**Author:** ![hybrid\_dogfish](https://avatars.discourse-cdn.com/v4/letter/h/a587f6/32.png) [@hybrid\_dogfish](https://boards.straightdope.com/u/hybrid_dogfish)\ **Post date:** [December 16, 2004, 9:39pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/5 "2004-12-16T21:39:14Z")
Well, whilst driving through Vermont I saw signs saying that traffic lights were timed to require frquent stops, 😕 . So it would seem that in some places at least they time the lights to ensure that you _won’t_ get all green. :mad: 😉 ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [December 16, 2004, 9:51pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/6 "2004-12-16T21:51:03Z")
> [@Severian](#): > > Not to mention those that change based on the presence of a vehicle waiting at a red. But those aren’t timers. 🙂 ---
**Author:** ![Telemark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/telemark/32/372_2.png) [@Telemark](https://boards.straightdope.com/u/Telemark)\ **Post date:** [December 16, 2004, 9:55pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/7 "2004-12-16T21:55:24Z")
> [@hybrid\_dogfish](#): > > Well, whilst driving through Vermont I saw signs saying that traffic lights were timed to require frquent stops, 😕 . It’s quite common. Local residents/businesses don’t want people flying through their areas. Lights that don’t allow people to cruise at 50 MPH make sure that people drive slowly and/or don’t use that local route as an express route. Do a search on “traffic calming” and you’ll find all sorts of methods used to slow traffic down. ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [December 16, 2004, 9:55pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/8 "2004-12-16T21:55:32Z")
While it might be possible to synchronise lights on a one-way street (provided that you did not care about synchronising the cross streets), I don’t think that it would be possible on a two-way street, unless the cross streets were at regular intervals, corresponding with the speed driven divided by the total time of each traffic-light cycle. (For example, if the speed was 60 km/hour, and the cycle was a minute, then the cross streets would have to occur at multiples of half a kilometer.) ---
**Author:** ![MovieMogul](https://avatars.discourse-cdn.com/v4/letter/m/f08c70/32.png) [@MovieMogul](https://boards.straightdope.com/u/MovieMogul)\ **Post date:** [December 16, 2004, 10:02pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/9 "2004-12-16T22:02:26Z")
When I was in high school, the local paper had an article on traffic timers that included a map of all the timed streets (major thoroughfares) along with the speed for which they were timed. And by gum, the map worked (except for, say, rush hour)–if you changed (usually reduced) your speed to synch with among the first of the greens, you could often hit 8 or 9 subsequent ones without a problem. ---
**Author:** ![Severian](https://avatars.discourse-cdn.com/v4/letter/s/49beb7/32.png) [@Severian](https://boards.straightdope.com/u/Severian)\ **Post date:** [December 16, 2004, 10:08pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/10 "2004-12-16T22:08:35Z")
> [@friedo](#): > > But those aren’t timers. 🙂 Assume the “those” in my post refers to “traffic lights” and we’ll be okay. Although, one could argue that it is a timer. A timer which has its duration modified based on the presence of a waiting vehicle. ---
**Author:** ![MrFantsyPants](https://avatars.discourse-cdn.com/v4/letter/m/7ba0ec/32.png) [@MrFantsyPants](https://boards.straightdope.com/u/MrFantsyPants)\ **Post date:** [December 16, 2004, 10:18pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/11 "2004-12-16T22:18:43Z")
The way to hit al greens is to put a little strobelight at the right frequency on top of you car. Around here, that is how emergency vehicles make things work out for them. ---
**Author:** ![VenusProbe](https://avatars.discourse-cdn.com/v4/letter/v/e495f1/32.png) [@VenusProbe](https://boards.straightdope.com/u/VenusProbe)\ **Post date:** [December 16, 2004, 10:24pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/12 "2004-12-16T22:24:24Z")
> [@MrFantsyPants](#): > > The way to hit al greens is to put a little strobelight at the right frequency on top of you car. > > Around here, that is how emergency vehicles make things work out for them. Around here the buses use em too! One of the days… ---
**Author:** ![TheLoadedDog](https://avatars.discourse-cdn.com/v4/letter/t/35a633/32.png) [@TheLoadedDog](https://boards.straightdope.com/u/TheLoadedDog)\ **Post date:** [December 16, 2004, 10:56pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/13 "2004-12-16T22:56:26Z")
Many traffic lights have a timer _and_ sensors. On a busy intersection during the morning and evening peak, the sensors all four ways will be loaded all the time anyway, so they become redundant, and the timer kicks in. When it gets quieter, the sensors take over. Trying to get all greens is a very inexact science. ---
**Author:** ![DMark](https://avatars.discourse-cdn.com/v4/letter/d/e68b1a/32.png) [@DMark](https://boards.straightdope.com/u/DMark)\ **Post date:** [December 16, 2004, 11:40pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/14 "2004-12-16T23:40:21Z")
Will never happen in Beverly Hills on Santa Monica Blvd. They have all the lights set to go green at the same time (as far as the eye can see) and then all go red at the same time. Only if there is no traffic and you were going maybe 184 MPH could you shoot through there in that short window. I think they do it intentionally to annoy drivers so they will NOT drive through Beverly Hills. ---
**Author:** ![JustWrightin](https://avatars.discourse-cdn.com/v4/letter/j/a87d85/32.png) [@JustWrightin](https://boards.straightdope.com/u/JustWrightin)\ **Post date:** [December 16, 2004, 11:47pm UTC](https://boards.straightdope.com/t/how-to-get-all-green-lights/280211/15 "2004-12-16T23:47:37Z")
> [@DMark](#): > > Will never happen in Beverly Hills on Santa Monica Blvd. They have all the lights set to go green at the same time (as far as the eye can see) and then all go red at the same time. Only if there is no traffic and you were going maybe 184 MPH could you shoot through there in that short window. > > I think they do it intentionally to annoy drivers so they will NOT drive through Beverly Hills. with better to do areas you get associations like P.E.T.A they dont want you to hit a stray dog or cat.